The discussion below is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.
Aspects of the present invention relate to a rollo assembly, comprising a flexible rollo screen, a rotatable winding shaft to which a first end of the rollo screen is attached for being wound on or off said winding shaft and two opposite longitudinal guides extending in a longitudinal direction perpendicularly to the winding shaft for guiding opposite sides of the rollo screen, wherein the rollo screen further is provided with longitudinally spaced elongate stiffeners extending substantially in a transverse direction in parallel to the winding shaft between the opposite sides of the rollo screen and attached to the flexible rollo screen, which stiffeners are biased for assuming a curved shape in said transverse direction.
Such a rollo assembly, as shown for example in EP-A-1 769 958, often is used in a vehicle for shading a roof opening of an open roof construction. The curved shape in said transverse direction is used for conforming the shape of the rollo screen (when wound off from the winding shaft) to a curved shape of an interior side (headliner) of the vehicle roof.
Although such curved stiffeners are effective in offering the rollo screen the desired curved shape, the stiffness needed for maintaining the rollo screen in said curved shape requires substantial forces for straightening the stiffeners when the rollo screen with stiffeners are wound onto the winding shaft. These forces which act directly on the stiffeners, and thus too act on the rollo screen, may lead to permanent deformations (depressions or markings) in the rollo screen which in a negative way influence the appearance of the rollo screen (and which further in some instances may shorten the lifespan of the rollo screen).